This easy worksheet builds main idea and supporting details skills with friendly dog-themed practice for second graders. Kids first sort six sentences into About Dogs or Not About Dogs, deciding whether facts about cats napping, birds building nests, and frogs near ponds belong with sentences about dogs playing fetch and learning tricks.

Fill-in-the-blank items teach key words like topic, mostly, and off-topic, and true or false statements clear up the common mix-up between topic and main idea. Students leave understanding that the main idea is what a passage is mostly about and that every sentence should match it.